Search

A series of chelating N N proligands, 3‐(2‐pyridyl)‐5‐alkyl‐1,2,4‐triazoles (HLAlk), where alkyl=methyl, ethyl, isopropyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl was used as building blocks for designing of coordination compounds. Their reaction with an equimolar amount of [PdCl2(CH3CN)2] led to formation of series of six novel palladium complexes [Pd(HLAlk)Cl2], in which ligands are coordinated in the acid form. New proligands and Pd(II) complexes were characterized by IR, 1H and 13C NMR spectroscopy and elemental analysis. The Pd(II) complexes showed an unusual downfield shift in 1H NMR of the aliphatic proton that is the closest to triazole ring, which suggests the C−H...Cl hydrogen bonding, supported by X‐ray data for Pd(HLc−Pr)Cl2 and Pd(HLc−Bu)Cl2. [ABSTRACT FROM AUTHOR]

The title compound, bis[μ-2,2′-(4H-1,2,4-triazole-3,5-diyl)diacetato]bis[diaquacopper(II)] dihydrate, [Cu2(C6H5N3O4)2(H2O)4]·2H2O, is a dinuclear octahedral CuII triazole-based complex. The central copper atoms are hexa-coordinated by two nitrogen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxylate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water molecules. Two additional solvent water molecules are linked to the title molecule by O—H⋯N and O⋯H—O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supramolecular chains running along the a-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H⋯O/O⋯H (53.5%), H⋯H (28.1%), O⋯O (6.3%) and H⋯C/C⋯H (6.2%) interactions. The crystal studied was twinned by a twofold rotation around [100]. [ABSTRACT FROM AUTHOR]

Although it is known (from the observations of medical professionals) that cigarette smoke negatively affects maxillofacial prostheses, especially through staining/discoloration, systematic research in this regard is limited. Herein, the color modifications of M511 maxillofacial silicone, unpigmented and pigmented with red or skin tone pigments, covered with mattifiers, or with makeup and mattifiers, and directly exposed to cigarette smoke, were investigated by spectrophotometric measurements in the CIELab and RGB color systems. The changes in color parameters are comparatively discussed, showing that the base silicone material without pigmentation and coating undergoes the most significant modifications. Visible and clinically unacceptable changes occurred after direct exposure to only 20 cigarettes. By coating and application of makeup, the material is more resistant to color changes, which suggests that surface treatments provide increased protection to adsorption of the smoke components. The dynamic water vapor sorption (DVS) measurements indicate a decrease of the sorption capacity in pigmented versus unpigmented elastomers, in line with the changes in color parameters. [ABSTRACT FROM AUTHOR]

Quite recently we discovered that copper(II) complexes with isomeric morpholine-thiosemicarbazone hybrid ligands show good cytotoxicity in cancer cells and that the molecular target responsible for this activity might be tubulin. In order to obtain better lead drug candidates, we opted to exploit the power of coordination chemistry to (i) assemble structures with globular shape to better fit the colchicine pocket and (ii) vary the metal ion. We report the synthesis and full characterization of bis-ligand cobalt(III) and iron(III) complexes with 6-morpholinomethyl-2-formylpyridine 4N-(4-hydroxy-3,5-dimethylphenyl)-3-thiosemicarbazone (HL1), 6-morpholinomethyl-2-acetylpyridine 4N-(4-hydroxy-3,5-dimethylphenyl)-3-thiosemicarbazone (HL2), and 6-morpholinomethyl-2-formylpyridine 4N-phenyl-3-thiosemicarbazone (HL3), and mono-ligand nickel(II), zinc(II) and palladium(II) complexes with HL1, namely [CoIII(HL1)(L1)](NO3)2 (1), [CoIII(HL2)(L2)](NO3)2 (2), [CoIII(HL3)(L3)](NO3)2 (3), [FeIII(L2)2]NO3 (4), [FeIII(HL3)(L3)](NO3)2 (5), [NiII(L1)]Cl (6), [Zn(L1)Cl] (7) and [PdII(HL1)Cl]Cl (8). We discuss the effect of the metal identity and metal complex stoichiometry on in vitro cytotoxicity and antitubulin activity. The high antiproliferative activity of complex 4 correlated well with inhibition of tubulin polymerization. Insights into the mechanism of antiproliferative activity were supported by experimental results and molecular docking calculations. [ABSTRACT FROM AUTHOR]

In the title complex, [U(C10H7N3O3)O2(CH3OH)]n, the UVI cation has a typical penta­gonal–bipyramidal environment with the equatorial plane defined by one N and two O atoms of one doubly deprotonated 2-[5-(2-hy­droxy­phen­yl)-1H-1,2,4-triazol-3-yl]acetic acid ligand, a carboxylate O atom of the symmetry-related ligand and the O atom of the methanol mol­ecule [U—N/Oeq 2.256 (4)–2.504 (5) Å]. The axial positions are occupied by two oxide O atoms. The equatorial atoms are almost coplanar, with the largest deviation from the mean plane being 0.121 Å for one of the O atoms. The benzene and triazole rings of the tetra­dentate chelating–bridging ligand are twisted by approximately 21.6 (2)° with respect to each other. The carboxyl­ate group of the ligand bridges two uranyl cations, forming a neutral zigzag chain reinforced by a strong O—H⋯O hydrogen bond. In the crystal, adjacent chains are linked into two-dimensional sheets parallel to the ac plane by C/N—H⋯N/O hydrogen bonding and π–π inter­actions. Further weak C—H⋯O contacts consolidate the three-dimensional supra­molecular architecture. In the solid state, the compound shows a broad medium intensity LMCT transition centred around 463 nm, which is responsible for its red colour. [ABSTRACT FROM AUTHOR]

An original approach for the design of hydrophobized heterogeneous platinum‐based catalytic systems is reported here. Heterogenization was performed by depositing the platinum precursor (H2PtCl6) on macroporous styrene‐divinylbenzene (SDVB) beads with a high surface area, ∼330 m2 g−1, as determined by N2 sorption data, followed by treating with 1,1,3,3‐tetramethyldisiloxane (TMDS) as Pt(IV) reducing agent without the need of special conditions. Simultaneously, the coupling by SiOSi bonds of the TMDS oxidation or hydrolysis intermediates endowed the SDVB‐Pt systems with an enhanced hydrophobicity (up to 10 times higher than that of SDVB support). In addition, to obtain an optimum catalytic system, which stabilize the supported platinium against leaching, several mixtures of TMDS with other methylsiloxane precursors, namely, methyltrimethoxysilane (MTMS), α,ω‐bis(trimethylsiloxy)poly(dimethylsiloxane‐H‐methylsiloxane) (PDMHS), and α,ω‐bis(trimethylsiloxy)poly(dimethylsiloxane‐co‐vinylmethylsiloxane) (PDMVS), have been systematically investigated. The reduction of platinum, visible by an instant change in the color from yellow to black, was confirmed by X‐ray photoelectron spectroscopy analysis, while its total content in the samples was determined quantitatively by atomic absorption spectroscopy. The obtained systems have been preliminarily assessed for catalytic activity in the hydrosilylation of 1,3‐bis(vinyl)tetramethyldisiloxane and allyl alcohol with TMDS, and 1‐hexene with trimethoxysilane, as model reactions. The results indicate the high suitability of these systems as catalysts for the selective anti‐Markovnikov hydrosilylation of alkenes, as well as for the very fast oxidation‐condensation homocoupling of H‐silanes in presence of a green oxidation agent (air), under mild conditions, with the release of hydrogen and its in situ addition to the double bond. [ABSTRACT FROM AUTHOR]

The title compound, bis-[μ-2,2'-(4 H -1,2,4-triazole-3,5-di-yl)di-acetato]-bis-[di-aqua-copper(II)] dihydrate, [Cu 2 (C 6 H 5 N 3 O 4 ) 2 (H 2 O) 4 ]·2H 2 O, is a dinuclear octa-hedral Cu II triazole-based complex. The central copper atoms are hexa-coordinated by two nitro-gen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxyl-ate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water mol-ecules. Two additional solvent water mol-ecules are linked to the title mol-ecule by O-H⋯N and O⋯H-O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supra-molecular chains running along the a -axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H⋯O/O⋯H (53.5%), H⋯H (28.1%), O⋯O (6.3%) and H⋯C/C⋯H (6.2%) inter-actions. The crystal studied was twinned by a twofold rotation around [100]., (© Vynohradov et al. 2024.)

Quite recently we discovered that copper(II) complexes with isomeric morpholine-thiosemicarbazone hybrid ligands show good cytotoxicity in cancer cells and that the molecular target responsible for this activity might be tubulin. In order to obtain better lead drug candidates, we opted to exploit the power of coordination chemistry to (i) assemble structures with globular shape to better fit the colchicine pocket and (ii) vary the metal ion. We report the synthesis and full characterization of bis-ligand cobalt(III) and iron(III) complexes with 6-morpholinomethyl-2-formylpyridine 4 N -(4-hydroxy-3,5-dimethylphenyl)-3-thiosemicarbazone (HL1), 6-morpholinomethyl-2-acetylpyridine 4 N -(4-hydroxy-3,5-dimethylphenyl)-3-thiosemicarbazone (HL2), and 6-morpholinomethyl-2-formylpyridine 4 N -phenyl-3-thiosemicarbazone (HL3), and mono -ligand nickel(II), zinc(II) and palladium(II) complexes with HL1, namely [Co III (HL 1 )(L 1 )](NO 3 ) 2 (1), [Co III (HL 2 )(L 2 )](NO 3 ) 2 (2), [Co III (HL 3 )(L 3 )](NO 3 ) 2 (3), [Fe III (L 2 ) 2 ]NO 3 (4), [Fe III (HL 3 )(L 3 )](NO 3 ) 2 (5), [Ni II (L 1 )]Cl (6), [Zn(L 1 )Cl] (7) and [Pd II (HL 1 )Cl]Cl (8). We discuss the effect of the metal identity and metal complex stoichiometry on in vitro cytotoxicity and antitubulin activity. The high antiproliferative activity of complex 4 correlated well with inhibition of tubulin polymerization. Insights into the mechanism of antiproliferative activity were supported by experimental results and molecular docking calculations.

In the title complex, [U(C 10 H 7 N 3 O 3 )O 2 (CH 3 OH)] n , the U VI cation has a typical penta-gonal-bipyramidal environment with the equatorial plane defined by one N and two O atoms of one doubly deprotonated 2-[5-(2-hy-droxy-phen-yl)-1 H -1,2,4-triazol-3-yl]acetic acid ligand, a carboxyl-ate O atom of the symmetry-related ligand and the O atom of the methanol mol-ecule [U-N/O eq 2.256 (4)-2.504 (5) Å]. The axial positions are occupied by two oxide O atoms. The equatorial atoms are almost coplanar, with the largest deviation from the mean plane being 0.121 Å for one of the O atoms. The benzene and triazole rings of the tetra-dentate chelating-bridging ligand are twisted by approximately 21.6 (2)° with respect to each other. The carboxyl-ate group of the ligand bridges two uranyl cations, forming a neutral zigzag chain reinforced by a strong O-H⋯O hydrogen bond. In the crystal, adjacent chains are linked into two-dimensional sheets parallel to the ac plane by C/N-H⋯N/O hydrogen bonding and π-π inter-actions. Further weak C-H⋯O contacts consolidate the three-dimensional supra-molecular architecture. In the solid state, the compound shows a broad medium intensity LMCT transition centred around 463 nm, which is responsible for its red colour., (© Vashchenko et al. 2024.)